I’m not sure but I think DNA
        
             
        
        
        
Answer:
d. an immediate increase in the concentration of antibodies, followed by a slow decline.
Explanation:
The Primary Immune Response is mediated by antibodies, which are gamma globulin proteins formed by plasma cells (B lymphocytes). Plasmocyte is a differentiated B lymphocyte capable of actively secreting antibodies.
Antibodies are produced with the main function of neutralizing and eliminating an antigen that stimulated their production. This elimination process is done in various ways through complement fixation, opsionization, anaphylactic reaction (mast cell degranulation), substance neutralization, agglutination, etc.
To neutralize the antigen, the primary immune response promotes an immediate increase in antibody concentration. This is usually a quick process.  This concentration usually begins to decline in a slow process, but it will vary depending on the antigen.
 
        
             
        
        
        
It depends on the life stage that the star is in. Currently, in the mid-life stage, the sun is still fusing hydrogen into helium, so the maximum here is helium; however, far in the future when the star is nearing its final days, it can fuse atoms into elements as heavy as iron and nickel.
        
             
        
        
        
RICE is the staple of South Korean diet while CORN is a staple of the US diet.
These preferences for food in these two countries are influenced by historical and social factors. 
Most of the food in South Korea are usually prepared from rice while in the US most of the staple food are prepared from corn.
        
             
        
        
        
The right option is; dark-field microscope
A light microscope that makes the specimen appear light on a dark background is called a dark field microscope.
Dark field microscopes are light microscopes that are used in different ways to clearly view various specimens that are unstained, transparent, and hard to see using a light field unit. Dark field microscopes are very effective because they show the details of unstained and live samples. It is also very simple to use, and inexpensive to set up.